title: Experimental and computational studies of nJ(77Se, 1H) selenium-proton couplings in selenoglycosides.
abstract: Selenoglycosides are important starting materials in synthetic carbohydrate chemistry and play a role in biological interactions as well. Both aspects are influenced by the conformation around the glycosidic bond. Here, we present a combined experimental and computational approach to measure and evaluate (n)J((77)Se, (1)H) coupling constants for their use in conformational analysis. The measurements were carried out using a modified CPMG-HSQMBC pulse scheme which yields pure absorption antiphase multiplets to allow accurate determination of the (n)J(XH) values regardless of the size of the proton-proton couplings. Theoretical calculations were performed at the Second-Order Polarization Propagator Approach (SOPPA) level. Population-averaged values calculated for geminal and vicinal couplings are in a good agreement with experiment indicating an adequate theoretical level of the calculations. Experimental observations and computations alike have indicated that two-bond (77)Se-(1)H couplings, (2)J((77)Se, (1)H), in a H1-C1-Se-X moiety are very sensitive to the torsion angle around the C1-Se-bond and will, therefore, be useful for conformational studies.
authors.affiliation: Department of Chemistry, University of Debrecen, Debrecen, Hungary. kover@tigris.unideb.hu
authors.forename: Katalin E
authors.initials: KE
authors.lastname: Kövér
authors.forename: Ambati Ashok
authors.initials: AA
authors.lastname: Kumar
authors.forename: Yury Yu
authors.initials: YY
authors.lastname: Rusakov
authors.forename: Leonid B
authors.initials: LB
authors.lastname: Krivdin
authors.forename: Tünde-Zita
authors.initials: TZ
authors.lastname: Illyés
authors.forename: László
authors.initials: L
authors.lastname: Szilágyi
mesh_terms: D006027:Glycosides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000592:standards; D009942:Organometallic Compounds / Q000737:chemistry*; D011522:Protons; D011789:Quantum Theory; D012015:Reference Standards; D012643:Selenium / Q000737:chemistry*
chemical_list: D006027:Glycosides; D009942:Organometallic Compounds; D011522:Protons; D012643:Selenium